Valleys

A valley is an elongated low area often running between hills or mountains and typically containing a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams over a very long period. Some valleys are formed through erosion by glacial ice. These glaciers may remain present in valleys in high mountains or polar areas.

thumb|Wadi Ghuweir Trail to Feynan, Jordan

valleys formed by glacial scouring

thumb|A gully in Avaré, Brazil

dry creek or stream bed which temporarily or seasonally fills and flows after sufficient rain

U-shaped valley originally cut by water under the glacial ice near the margin of continental ice sheets

thumb|Glendun, one of the [[Glens of Antrim in Northern Ireland]] A glen is a valley, typically one that is long and bounded by gently sloped concave sides, unlike a ravine, which is deep and bounded by steep slopes. Glens are appreciated by tourists for their tranquility and scenery.

valley, that does not regularly sustain surface water flow

thumb|The River Spey flowing through Strathspey

small wooded valley, slope landform

thumb|upright=1.2|A dry gulch in the desert near Tamchy, [[Kyrgyzstan. The creek that may have run along the bottom of the gulch in the past has been diverted to a parallel aryk.]] A gulch is a deep V-shaped valley formed by erosion. It may contain a small stream or dry creek bed and is usually larger in size than a gully. Sudden intense rainfall upstream may produce flash floods in the bed of the gulch. thumb|Witches Gulch found in the Dells of the Wisconsin River

landform

thumb | right | alt=An example photograph of a Combe in Switzerland. | The "Combe de Dreveneuse" in Valais, Switzerland. A combe (; also spelled coombe or coomb and, in place names, comb) can refer either to a steep, narrow valley, or to a small valley or large hollow on the side of a hill; in any case, it is often understood simply to mean a small valley through which a watercourse does not run.